Johnson seized the early lead at the British Open on Thursday, shooting a 5-under 31 on the front side only four days after losing the John Deere Classic in a playoff.

Johnson didn't arrive at Muirfield until Monday morning after playing in the John Deere, where he made bogey on the 72nd hole and wound up losing in a three-man playoff. Nineteen-year-old Jordan Spieth captured the title on the fifth extra hole, becoming the youngest winner on the PGA Tour since 1931.

If Johnson was still kicking himself over that result, it didn't show. The 2007 Masters champion made an eagle at the par-5 fifth, then birdied the next two holes to claim the top spot on the board.

Johnson said of his round, "I hit some nice shots and obviously I putted really, really well." Johnson finished up with a 5-under 66 and currently holds the lead at The Open.

Other notables with solid first rounds are Dustin Johnson at 3-under and Phil Mickelson at 2-under.

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Mickelson's playing partner Rory McIlroy struggled to an 8-over 79. This year's US Open champion Justin Rose came in at 4-over.

McIlroy is ready to get some help after a fat 42 on the back nine almost surely put him out of contention in the British Open barely after it began.

Not with his swing. With his mind.

In McIlroy's words, "Sometimes I feel like I'm walking out there and I'm unconscious."

His round included, among other things, a putt that went into a bunker.

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The weather this morning at Muirfield was quite mild. In fact, the forecast hardly seemed fitting for a British Open: mostly sunny with temperatures climbing into the mid-70s.

But the course may be playing tough for reasons other than the weather. Some players have complained about the placement of pins that the R&A (the group that organizes the British Open) has set up.